#include<bits/stdc++.h>

using namespace std;
int *a, b;//a 是int* 而b是int


int main() {
    int x = 3, y = 4;
    int *p;
    p = &x;
    cout << "p=" << p << endl;
    *p = 5;
    cout << x << endl;//x=5
    //p++;//p不再指向x 而是指向x的下一个位置

    p--;//p不再指向x 而是指向x的前一个位置
    cout << "p=" << p << endl;
    *p = 5;//dangerous!!!
    cout << "x=" << x << ",y=" << y << endl;
    return 0;
}
